Vat Polymerization is a method in 3D printing to print 3D objects using photo-polymerization. Technically, Vat Polymerization produces an array using additive manufacturing (AM) processes for which a liquid resin contained in a vat is selectively solidified via light-activated polymerization (also called light-cured polymerization). Vat Polymerization Processes (VPP) allow a high accuracy-for-speed ratio and superior surface finishing, require neither high-powered lasers nor an inert gas building chamber, as in case of powder-based AM technologies. Applications of VPP include rapid prototyping for product design evaluation, indirect tooling for dies and molds such as tooling for jewelry or dental implants and direct digital manufacturing for niche markets or personalized medical devices such as dental aligners or hearing aids.
Currently available commercial VPP systems utilize either laser beam(s) for vector-by-vector scanning or digital light processing (DLP) projectors for blanket exposure and hardening of an entire layer. For the latter approach throughput and speed can be higher than for the former approach because building speed is independent because of the object geometry in the XY horizontal plane. It also eliminates the need for XY linear motion or scanning mirrors, leaving the need to only consider the mechanical elements along the Z axis in the system.
A thin-film transistor LCD (TFT-LCD) panel is an alternative to DLP projectors for a dynamic formation of photomask which can be projected on the resin surface. The price for a DLP development kit from commercial vendors is extremely high while the price of a high-resolution LCD panel is less than half of this, which is clearly more cost-effective. Screen pixel in a modern TFT-LCD mobile device have been reduced to 49 μm×49 μmm in size, and will continue to shrink as the semiconductor industry advances.
This may still appear inferior in comparison to DLP projection, where the light beam is split into separate pixels by millions of mirrors as small as 13.7 μmm×13.7 μmm. However, light reflected from micromirrors diverge, and pixels expand with increasing focus distance. Thus, square pixels become discernible under close inspection of a presentation screen. Liquid crystal displays, in contrast, have uniform pixel size over the entire area and accuracy characteristics are independent of scale. However, none of the prior studies has tried to benefit from specific liquid crystal display properties, such as the red-green-blue sub-components of a pixel.
In order to overcome the drawbacks in the prior art, the present invention introduces a novel low-cost software-based method of resolution and accuracy enhancement for the LCD type Vat Polymerization process. The particular design in the present invention not only solves the aforementioned problems, but is also easy to implement. Thus, the present invention has utility for the industry.